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宇宙工学・惑星科学・宇宙物理の最新プレプリント。

astro-ph.EP

Atmospheric Escape Rates of Planets in Stellar Tidal Fields from 3-D Hydrodynamic Simulations

Ritika Sethi, Morgan MacLeod, Sarah Millholland

Thermally driven atmospheric escape, including photo-evaporation and core-powered mass-loss, plays a key role in shaping the evolution of close-in exoplanets, yet most current models rely on simplified one-dimensional descriptions of atmospheric escape. In this work, we perform 3D hydrodynamic simulations of atmospheric outflows from a Jupiter-sized planet embedded in the gravitational potential of a solar-type host star, and compare these results with 1D models to identify the regimes where the…

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astro-ph.SR

Supergranulation as a Tracer of Solar-Cycle Variability

Irina N. Kitiashvili, Andrew A. Ngo, Spiridon Kasapis

Supergranulation is one of the dominant scales of near-surface solar convection and provides an important diagnostic for studying the interaction between convective flows, rotation, and magnetic activity. We develop an automated framework to identify and characterize supergranular structures using subsurface horizontal-velocity maps inferred from time-distance helioseismology. The method applies Laplacian-of-Gaussian detection to horizontal velocity divergence maps and combines this with magneti…

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astro-ph.GA

CHORD HI-Galaxy Survey Forecasts: Searching for nearby dark galaxies and high redshift giants

Akanksha Bij, Kristine Spekkens, Hans S. Hopkins, Michael G. Jones, Arnab Chakraborty, Simon Foreman, Alex S. Hill, Dustin Lang et al.

Population studies of gas-rich galaxies across the full range of Neutral Hydrogen (HI) masses that galaxies are known to exhibit ($10^5 \lesssim M_{\mathrm{HI}} \lesssim 10^{11} M_{\odot}$) remain limited by the need to conduct high-sensitivity, wide-band surveys across significant sky areas. The Canadian Hydrogen Observatory and Radio-transient Detector (CHORD) is a next-generation radio telescope that will significantly expand the census of HI-galaxies to date from untargeted drift-scan survey…

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astro-ph.GA

When galaxies cross cold fronts: wind tunnel simulations of ram pressure stripping

Elvis A. Mello-Terencio, Rubens E. G. Machado, Richards P. Albuquerque

Cluster collisions and mergers are among the most energetic phenomena in the low redshift Universe. These interactions disturb the intracluster medium creating regions with density and temperature discontinuities, such as sloshing spirals. There is evidence that such environments can influence galaxy evolution. This study aims to understand how a galaxy that crosses an environment with discontinuities in density and temperature can be affected. To this end, a set of simulations was conducted usi…

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astro-ph.GA

Too many quiescent late-type galaxies or a matter of misclassification?

J. L. Tous, S. I. Raimundo, H. Domínguez Sánchez

In the local Universe, the terms late-type and early-type are used to describe, respectively, disc galaxies with spiral arms and more bulge-dominated systems lacking spiral structure. These morphologies are often associated with different star formation levels, motivating the classical scenario where late-type and early-type galaxies are seen, respectively, as star-forming and "red and dead" systems. To build a comprehensive picture of galaxy evolution, we must understand the relationship betwee…

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astro-ph.GA

Laboratory spectroscopy, theoretical characterization, and astronomical search for syn-propenethial (CH2CHCHS)

Germán Molpeceres, Carlos Cabezas, Marcelino Agúndez, María Mallo, Yasuki Endo, Lucie Kolesniková, Gisela Esplugues, José Cernicharo et al.

We report the laboratory characterization of the higher-energy isomer of propenethial, syn-CH2CHCHS. While the lower-energy isomer, anti-CH2CHCHS, was detected in the interstellar medium during the QUIJOTE line survey of TMC-1, we report the non-detection of the syn isomer in the same source, deriving an upper limit to its column density of 1.5 $\times$ 10$^{10}$ cm$^{-2}$. A subsequent theoretical investigation into the origin of this non-detection reveals that the most plausible formation path…

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astro-ph.GAastro-ph.SR

Stellar Dynamics and Evolution of the Intermediate-Age Open Clusters NGC 2266 and NGC 2324

Cyrus Raj, D. Bisht, Ashish Raj

We present a refined astrometric and photometric analysis of the well-studied intermediate-age open clusters NGC 2266 and NGC 2324 using high-precision Gaia DR3 data, complemented by 2MASS and LAMOST DR7 catalogs. Probable cluster members are identified using unsupervised machine learning techniques. We apply both Gaussian Mixture Models (GMMs) and \texttt{pyUPMASK}. We find that the GMM-based membership sample yields a cleaner, more coherent cluster sequence in the Gaia CMDs than pyUPMASK. We i…

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astro-ph.IM

Map Multi-Tool: A Map-Based Approach to Modeling Beam Systematics for Cosmic Microwave Background Experiments

Cesiley L. King, Alec Hryciuk, Jeff McMahon, Johanna M. Nagy, John E. Ruhl

Cosmic microwave background (CMB) experiments use simulations of instrumental systematic effects to ensure high-fidelity measurements of cosmological parameters. Quantifying the expected magnitude of these effects enables experiments to improve designs, set performance requirements, and understand potential measurement biases from residual systematics. Here we present a new simulation framework, called Map Multi-Tool (MMT), which models beam-related systematics for CMB instruments using a map-ba…

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astro-ph.GAastro-ph.SR

Constraining young massive cluster properties with radio-continuum observations: The Arches cluster

M. Cano-González, R. Schödel, A. Alberdi, F. Najarro, J. Moldón, M. Pérez-Torres, F. Nogueras-Lara

The Arches cluster, located in the Galactic Centre (GC) is one of the best astrophysical laboratories to study the properties of massive stars and young massive clusters (YMCs). However, several fundamental parameters of the Arches cluster remain uncertain. Our goal is to constrain key cluster parameters (cluster age, mass, and initial mass function, IMF) by comparing the observed stellar radio flux density distribution of the Arches cluster to those derived from a set of synthetic clusters. We…

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astro-ph.IM

Shack-Hartmann wavefront sensor slope measurement algorithm robust to scintillation and sensor saturation

Timoth{é}e Vene, Laurent M Mugnier, Aur{é}lie Montmerle-Bonnefois, Jean-Marc Conan

High throughput optical communication links require the use of adaptive optics (AO) to compensate for atmospheric turbulence even in strong perturbation conditions and at low elevation. Considering the intensity fluctuations brought by scintillation, we present a new slope measurement algorithm for the Shack--Hartmann wavefront sensor (SHWFS), based on a joint maximum likelihood approach. We show that this estimator is robust to sensor saturation and widens by more than two orders of magnitude t…

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astro-ph.IM

The Wide-field Spectroscopic Telescope (WST): design trade-offs for the low-resolution multi-object spectrograph instrument

Dimitri Buffat, Will Saunders, Kjetil Dohlen, Laurence Tresse, David Lee, Roland Bacon, Andrea Bianco, Laurane Fréour et al.

The Wide-field Spectroscopic Telescope (WST) is a planned 12-meter-class dedicated spectroscopic facility designed to address key scientific challenges through large spectroscopic surveys. This paper presents design and performance trade-offs for the Low-Resolution Multi-Object Spectrograph (MOS-LR) instrument. With a multiplex of 30,000 covering a field of view of 3.1 square degrees, this instrument will provide unprecedented survey efficiency, an order of magnitude beyond those of current faci…

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astro-ph.EPastro-ph.IM

Disk-averaged spectrum generation for spherically symmetric planets and moons

Nicholas A. Teanby

Here I present a simple and efficient method for generating a disk-averaged planetary spectrum. The technique uses a weighted average of component spectra generated on an irregular grid of offsets from the planet center. This accounts for variations in center to limb brightness and emission from beyond the limb, which is important for bodies with extended atmospheres such as Saturn's moon Titan. The method assumes spherically symmetric emission and requires a grid of component spectra fine enoug…

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astro-ph.SR

An Halpha survey of infrared bow-shocks around OB-type stars

Kuljeet Singh Saddal, Michaela Kraus, Dieter H. Nickeler, Tiina Liimets, Sergey Karpov, Olga V. Maryeva

Bow shocks (BSs) around massive stars are commonly identified in mid-infrared (MIR) surveys. In contrast, systematic optical investigations of these structures remain scarce with only a few possible detections reported so far. We performed a targeted Halpha imaging survey of 78 IR BS candidates compiled from literature catalogues. Observations were obtained with multiple ground-based facilities and complemented with archival MIR images from Spitzer and WISE. For the detected bow structures, geom…

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astro-ph.HE

R-process nucleosynthesis from magnetar giant flares in neutron star--white dwarf mergers: A unified picture for peculiar long gamma-ray bursts

Shu-Qing Zhong, Long Li, Le Zou, Ji-Gui Cheng, Yan-Zhi Meng, Jia-Hong Gu

Peculiar long gamma-ray bursts (GRBs), exemplified by GRBs 211211A and 230307A, exhibit a long-duration multi-component prompt emission, an X-ray plateau in their afterglow, and a kilonova signature. Their origin remains highly debated. In this work, we present a unified picture for these events based on neutron star--white dwarf (NS--WD) mergers involving a pre-merger magnetar and a massive WD. In this picture, tidal disruption of the WD forms a constant-entropy accretion disk. Hyperaccretion f…

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astro-ph.IM

Modelling Radio Frequency Interference on the Lunar Farside

Charlie K. Ashe, Ella J. Marshall, Evan F. Keane, Steve Prabu, Richard Lynch, David R. DeBoer

Technological progress is a double-edged sword in the world of radio astronomy: improvements in antennas, receivers, and digital backends increase sensitivity, but rapid growth in terrestrial and orbital communications has caused a steep rise in radio-frequency interference (RFI). Modern datasets have become increasingly contaminated by RFI that is difficult to remove and can mimic or obscure astrophysical signals, complicating the search for objects such fast radio bursts (FRBs), pulsars, and t…

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astro-ph.SRcs.CV

A Modern ConvNet for Solar Filament Detection

J. R. Hu, Q. Hao, Z. Zheng, P. F. Chen, C. Li, Y. Meng

Automated solar filament detection using deep learning faces several challenges. Semantic segmentation of solar filaments is a complicated multiscale feature extraction task with long-tail distribution. Furthermore, a large-scale, highly complete, and finely detailed dataset has become mandatory for providing abundant information. To address these challenges, we present a series of machine learning approaches to develop a solar filament detection workflow that performs superbly. First, we manual…

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astro-ph.GAastro-ph.HE

Time-Domain Dust Astrophysics. I. Polarization Flares, Polarization-Angle Reverberation, and Fossil Imprints in Supernova-Illuminated Clouds

Thiem Hoang

Cosmic transients can dramatically enhance the local radiation field on timescales of days to months. Using the time-domain TransRAT framework, which self-consistently evolves grain heating, alignment, rotational disruption, and switching of the alignment axis between the magnetic field (B-RAT) and the radiation direction (k-RAT), we predict the time-dependent dust polarization of a dense cloud illuminated by a Type~IIP supernova at different distances. We identify four key signatures. First, fo…

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astro-ph.SR

Identification of unresolved binaries in the VVV b294 tile: A Pro-Am collaboration using the Virtual Observatory

M. Cortés-Contreras, P. Cruz, E. Solano, J. L. Navarro, T. Poyato Romero, R. Benavides Palencia, C. Cagigal-Olay, M. Zamora Rodríguez et al.

Stellar binaries and multiples are common objects. Their identification and characterization are primarily limited by the angular resolution of current instrumentation, survey depth and dynamic range. Towards the Galactic plane, stellar crowding further complicates these studies. We aim to identify unresolved binaries with good astrometric solutions and M dwarf primaries in the b294 field from the Vista Variables in the Vía Láctea (VVV) survey using publicly available data. We examine the catalo…

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astro-ph.IMphysics.ins-det

The beamformed trigger of RNO-G: its design and in-field performance

RNO-G Collaboration, :, S. Agarwal, J. A. Aguilar, N. Alden, S. Ali, P. Allison, M. Betts et al.

The Radio Neutrino Observatory in Greenland (RNO-G) is a neutrino detector under construction at Summit Station, with 8 out of a planned 35 stations currently deployed. We have designed and deployed a new phased array (PA) trigger based on delay-and-sum beamforming and power integration. This trigger improves detector performance by suppressing thermal noise and better targeting neutrino-induced Askaryan signals. The new PA trigger has been deployed since the 2025 season. The trigger performance…

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astro-ph.GAastro-ph.HE

Cosmic ray heating of cold streams: Implications for the gas supply and growth of massive galaxies

Ellis R. Owen, Nicolas Ledos, Evangelia Ntormousi, Shinsuke Takasao, Kentaro Nagamine, Sebastiano Cantalupo

Recent observations have demonstrated the presence of cosmic rays (CRs) in cosmic-web filaments. Cold streams supply gas inflows from these filaments into massive galaxies during the cosmic noon. As these streams are expected to be magnetised, external cosmic-web CRs may become entrained with this inflowing gas. We aim to determine whether this externally-supplied CR population can deposit energy to alter or disrupt the supply of cold gas to galaxies. We couple a spectrally-resolved CR transport…

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astro-ph.SR

A survey for variable young stars with small telescopes - XI. Spot Lifetimes and Coverage Distributions

Dirk Froebrich, Carys Herbert, Aleks Scholz, Benjamin W. Ryan, Siegfried Vanaverbeke, Jochen Eislöffel, Cledison Marcos da Silva, Michel Michaud et al.

We present a homogeneous analysis of rotational variability and spot properties in young stellar objects across multiple star-forming regions observed by the Hunting Outbursting Young Stars (HOYS) project. From over 2000 candidate members, we identify 144 YSOs with robust periodic signals and well-constrained multi-band amplitudes. The sample has a median age of $\sim$1~Myr, effective temperatures of 3500--6500~K (masses $\sim$0.6--2~M$_\odot$), and is dominated by Class~2 objects, one third of…

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astro-ph.HE

Evolution of Calvera and Descendants of Calvera-like Central Compact Objects

Ali Arda Gencali, Unal Ertan, Fatmanur Ertugrul, Seyda Demirok, Ndiogou Niang

Calvera (1RXS J141256.0+792204) is an isolated neutron star recently classified as a central compact object (CCO) after its association with the supernova remnant (SNR) candidate G118.4+37.0. In this work, we investigate the long-term evolution and descendants of Calvera and the CCOs with similar initial conditions in the fallback disc model. We show that the observed spin period, period derivative, and X-ray luminosity of Calvera can be reproduced simultaneously with a magnetic field strength o…

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astro-ph.HEgr-qc

Transport Properties of the MRI in Differentially Rotating Neutron Stars

Harshraj Bandyopadhyay, Peter Hammond, David Radice

We perform three-dimensional, high-resolution, general-relativistic magnetohydrodynamics (GRMHD) simulations of the magnetorotational instability (MRI) in differentially rotating neutron stars. We consider both high-mass models which collapse either promptly, or due to the outward transport of angular momentum removing rotational support, and lower-mass models, which remain stable even after solid-body rotation has been achieved. We measure effective transport coefficients of the resulting turbu…

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astro-ph.SR

On the Modeling of Kink Oscillations in Fine-Structured Coronal Loops with Field-aligned Nonlinear Longitudinal Disturbances

Shakti Singh, Balveer Singh, V. S. Pandey, Shilpa Patra, Preeti Verma, Peter H. Yoon

We investigate the influence of nonlinear longitudinal disturbances, triggered by an initial field-aligned velocity flow, on the damping of standing kink oscillations in fine-structured, cool coronal loop strands under isobaric conditions. Using two-dimensional ideal MHD simulations, we model different realistic flow geometries, bounded, unbounded, and external, and quantify their impact on wave excitation, damping, and energy leakage. Our modelled loop strand incorporates strong density contras…

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hep-exastro-ph.IMhep-ph

Dark Matter Searches with Sodium Iodide Detectors

Maria Martinez, Reina H. Maruyama, Maria Luisa Sarsa

The search for the identity of dark matter remains one of the most intriguing challenges in physics today, driving innovative advances in experiment and theory. Thallium-doped sodium iodide (NaI) detectors have played a pivotal role in this context. This review outlines the scientific landscape surrounding NaI detectors, emphasizing their role in the broader context of dark matter research. We begin with a brief description of characteristics that make these detectors well-suited for dark matter…

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astro-ph.GA

Kinetic and H-atom product study of the C + C6H6 reaction at low temperatures

Kevin M. Hickson, Jean-Christophe Loison

The reactions of atomic carbon in its ground electronic state configuration, C(3P), are potentially important processes in astrochemistry due to the large abundance of C(3P) atoms in the interstellar medium (ISM) and its high overall reactivity towards a wide range of molecules. Although benzene, C6H6, has not been detected in the dense ISM, its presence at high abundance levels is inferred through the detection of functionalized derivatives. Here we present a combined experimental and astrochem…

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hep-phastro-ph.SRhep-ex

A High-Precision Numerical Framework for Time-Varying Solar Neutrino Flux with Full Earth Matter Oscillation Corrections for Global Underground Laboratories

Keyu Han, Isabella Yin, Kaoru Yagi, Kevin Yifan Jiang, Xiangpan Ji, Shaomin Chen

Solar neutrinos have been studied for over half a century to test both the Standard Solar Model and the electroweak sector of the Standard Model of particle physics. Contemporary experiments are now entering an era of high-precision measurements, demanding corresponding theoretical predictions with sub-percent accuracy to enable meaningful comparison. In this paper, we identify and analyze the essential physical and computational components required to compute solar neutrino fluxes with high fid…

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astro-ph.GAastro-ph.EPastro-ph.IMastro-ph.SR

A Split-Flux Method for Dust-Gas Two-Fluid Simulations from Strong to Weak Coupling

Kazunari Iwasaki

We develop a new method for simulating pressureless fluids of neutral dust coupled to magnetohydrodynamic gas through dust-gas drag. It has been pointed out that, in the strong-coupling regime, dust-gas multifluid methods suffer from artificial variations in the dust-to-gas mass ratio when the dust and gas are evolved with independent numerical fluxes. This problem arises from inconsistencies between the dust and gas mass fluxes. In the strong-coupling limit, the dust-to-gas mass ratio is advect…

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astro-ph.COastro-ph.GA

Constraining the $z \approx 1$ neutral hydrogen (HI) distribution

Minal Chhabra, Raghunath Ghara, Somnath Bharadwaj

We constrain the $z \approx 1$ HI distribution by jointly modeling two independent, existing observations of the 21-cm signal, the HI density parameter $Ω_{\rm HI}$ measured using uGMRT by stacking the 21-cm emission from blue, star-forming galaxies, and the 21-cm autocorrelation power spectrum (PS) measured using CHIME. We assign HI to the dark matter halos in a cosmological simulation using an HI mass-halo mass (HIHM) relation with three free parameters whose values we estimate by performing a…

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astro-ph.HEastro-ph.CO

Constraints on the magnetic field in the hadronic scenario for the origin of the radio halo in the A1795 galaxy cluster

P. Marchegiani, V. Vacca, F. Loi, F. Govoni, M. Murgia

The radio halo in the cool-core galaxy cluster A1795 has recently been proposed to be of hadronic origin, because it extends on a scale of the order of Mpc, where no turbulence is expected to be injected in a relaxed cluster. In this paper we aim to constrain the properties of the non-thermal protons and the cluster magnetic field strength under the hypothesis of a hadronic origin of the radio halo at the light of the available gamma ray upper limit in this cluster. We assume a radial profile an…

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